It should be understood that the term “mobile user” used throughout the specification includes mobile telecommunication units that communicate with a base station in a wireless telecommunication network by means of electromagnetic waves such as mobile wireless telephones and cellular telephones that are designed to exchange voice information with the base station. The term mobile user also includes hybrid devices such as personal communications systems that have both telephone and data communication features.
It is known to use a wireless network based location system to locate the position of an active phone or a transceiver unit in a network. Once such system is disclosed in U.S. Pat. No. 5,844,522 issued Dec. 1, 1998 to Sheffer et al. This system includes a plurality of agile vector sensor units for which one is installed at each antenna site in the network and the remote control monitoring station to which the wireless network users can call for assistance in the event of an emergency. The system is designed to locate a portable phone transceiver unit using the reverse voice channel signal transmitted by the transceiver unit. This is a real time position locator for the mobile telephone in the system and is responsive to an emergency condition.
However, this real time position location system involves additional equipment to be utilized at each cell site adding to the capital cost of the network.
Further, utilizing the base station cell site call record information does not provide for accurate position estimation of a mobile user because the network contains several repeater stations that amplify the signals propagating between the base station cell sites and the mobile users through repeater stations as well as change propagation delay time and phase between the base station cell site and the mobile user.
Accordingly, there is a need to develop a tracking and analyzing system for locating mobile users in a network over a given time period and within particular regions of the network that is not subject to errors introduced by the call signal propagating through a repeater station.